Subodhrohilla, thanks for your post, but this tool is not what I'm looking for

It's only change mac address of some device, I know how to change device mac address using ifconfig, without any special utils, but I want Network Manager to change mac before connect and change it back after disconnect, so it will be very useful. May be there are some hooks in Network Manager, can I ask it to run some special shell command before connect and after disconnect?